In the past year, we have completed planned assays on samples from the clinical protocol, Assessment of the Effects of A DPP-4-Specific Inhibitor (Sitagliptin/Januvia) on Immune Function in Healthy Individuals. Analysis of results is ongoing. Current analysis indicates that sitagliptin does not significantly alter most of the immune readouts we measured, including levels of plasma TGF-beta and other cytokines, and flow cytometry on PBMCs. Flow cytometry data collected include Treg analysis and expression of CD26 on lymphocyte subsets.